For example, a friend of mine mentioned Jewish women of a certain group she sees from time to time in her neighborhood.
These women dress in traditional Arab dress, meaning a black hijab around their head and shoulders, plus a long black robe.
My friend says it doesn't really bother her in principle (yet some others get personally offended & disgusted when they see these women), except that when she first encounters these women, she's tenses up and checks them out until she realizes they are Jewish women and not potential terrorists.
And others certainly feel the same.
In fact, I imagine that any Jew (including Jewish men) in the vicinity would do as my friend and surreptitiously keep an eye on this women for suspicious activity, including trying to gauge whether she might have a suicide bombers belt around her midriff.
It's hard to label these clothes as "tsniyut," even though the technical covering is halachically sound as far as the length & width go.
Even though many be-hijabed women worldwide are not looking to massacre Jews, some have made strenuous attempts to do just that in Eretz Yisrael.
Hence, when Jews spot a be-hijabed woman in a neighborhood never frequented by Muslim women, they are prudent to be wary until her intentions can be clarified.
So if your clothing is actually instilling anxiety or fear within your fellow frum Jews, that doesn't fit within the bounds of tsniyut (especially because such a style is causing men to look at such a woman with extra scrutiny).
At this point, one might make the argument that all frum women look scary to at least some people because of the incitement of secular media. So a secular person with no other knowledge of frum people might feel anxious upon seeing a frum woman in his grocery store, thinking that it's a Jewish Taliban invading the area.
The difference is that wariness around a black hijab is a reasonable response in Eretz Yisrael. Women dressed in such a style have attempted to murder Jews. Actually, male terrorists have also used hijab and other traditional Muslima coverings to disguise themselves as females and elude Israeli security.
The fear doesn't derive from media incitement or false prejudices.
If your own fellow frum Jews who understand tsniyus cannot help but suspect you are a terrorist when they see you, then this is obviously a breach in tsniyus, despite the careful attention to technical measurements.
Likewise, a book I have on Jewish women throughout the ages shows a photo of a group of Jewish women in ̶G̶r̶e̶e̶c̶e̶ ̶̶Tunisia from the year 1900. While their style of tsniyus was quite commendable at the time, the billowing head-to-toe all-encompassing white sheet with its pointy top gave me a lurch in the pit of my stomach when I first saw it.
For a moment, I thought it was a picture of the Ku Klux Klan (a murderously exclusive gang of bigots – one of their early murder victims was a white Republican senator – formed by Southern Democrats after the Civil War whose uniform consists of a billowing white robe, white covering over the face, and a pointy white head-covering).
Clearly, dressing in traditional Jewish G̶r̶e̶e̶k̶ ̶Tunisian attire today would not be tsnanuah.
So we see that tsniyut isn't just about measurements.
It IS about measurements – covering the necessary parts IS vitally important – but it's not ONLY the technical inches that count. Getting lost in the technicalities can actually produce a lack of tsniyus, as occurs with these Jewish women in hijab.
It's a certain mindset, a certain understanding; it contains nuance and most of all, a desire to imitate Hashem, who is also Hidden from the human eye. (Please see Why is It So Important to be Modest? for more.)
Despite the expansive width & generous length of the clothing, we should not dress like those who (possibly) hate us.
Tsniyut should not strike terror in the hearts of those around you.